Recently, manipulating an image as digital data has increased considerably, increased accompanied with the progress in the operation rate of computers and related network technology. Image information digitized by a device such as a scanner can be easily edited or processed by computer and text data or an illustration can be added to the digitized information. Hard copy materials such as materials for sublimation thermal transfer printing, fusion thermal transfer printing, ink-jet printing, electrostatic transfer printing, thermo-autochrome printing and a silver halide photographic light-sensitive material, are usable for making a hard copy according to the digitized image information. Of these, the silver halide photographic light-sensitive material, hereinafter also referred to simply as light-sensitive material, is frequently used for making a high quality hard copy since the light-sensitive material is considerably superior to the other printing materials in sensitivity and exhibited excellent gradation and image storage ability.
Besides, many kinds of apparatus for imagewise exposing the sight-sensitive material utilizing the digitized image information have recently been developed. Typical examples 64 thereof include ones using a scanning exposure method in which a light source such as a light emission diode, a gas laser, a semiconductor laser or a second harmonic generated image by a combination such the light emission element and a SHG element is used. Such a digital exposing apparatus is preferable since the light-sensitive material is exposed in a shorter time at a higher resolution.
However, the wavelength of the light for exposing and the exposing time can vary over a wide range since a variety of light sources are used in the exposing apparatus. Accordingly, a light-sensitive material is required so that a high quality print can be stably obtained even when any type of exposing apparatus is used since the quality of the print varies depending on the exposing apparatus used.
For example, in a material widely used for printing a visual approval image, blurring and color mixing of the image often occur since such a light-sensitive material is designed to stably provide a high quality image when the material is exposed through a color negative film. Specifically, the majority of usual light-sensitive materials are designed based on a relatively long wavelength light of from 440 to 470 nm with respect to the blue-sensitive silver halide emulsion and the blue-light absorbing anti-irradiation dye. Therefore, deterioration in the sharpness of the yellow image component, formation of a yellow blur is exhibited around black fine lines of the image and mixing of magenta or cyan color into the yellow image often occurs, depending on the blue light exposing system of the digital exposing apparatus.
Besides, chances of outputting a detailed and complex image such as the fine lines of text or geometrical patterns are increased with the digitization of an image. There is a strong demand to reproduce such images at high fidelity and stability.
It has been widely known that adding an anti-irradiation dye or colloidal silver into a coated layer will prevent blurring of an image. However, the photographic sensitivity of the light-sensitive material is lowered and the whiteness of the background deteriorates with an increase of the amount of the dye, even though the effect of the dye is increased. Accordingly, the requirements to stably obtain a high quality image in various exposing apparatus is difficult to satisfy by such a method.
A method for improving tone reproductions of details in shadow portions by regulation of the point gamma in the high density regions is disclosed in Japanese Patent Publication Open for Public Inspection (hereinafter, also denoted as JP O.P.I.) No. 8-36247, and a method for improving the character quality by regulating the latitude and N value of the magenta color-forming layer is disclosed in JP O.P.I. No. 10-20461.
However, still further improvement is demanded since deterioration of the sharpness of yellow image and mixing of magenta and cyan color in the yellow image are occurred depending on the blue-light exposing system of the digital exposing apparatus even when the above-mentioned technology is applied.
An image, including an image based on photographic image data such as a portrait, a landscape and a still life, hereinafter referred to a image scene, and an image of text, particularly an image of fine black text, in combination occurs often since image information digitized by a device such as a scanner can be easily edited or processed via a computer and data for text or an illustration can be added to the information. In such an image, it is necessary to satisfy two requirements at the same time to naturally reproduce the scene image and to reproduce the text image with no blurring.
It is necessary that the light-sensitive material be exposed to light with the light amount varied based on the image data to reproduce the digitized image data as a silver halide photographic image. At the time of exposure, a calibration operation is carried out so that the image density reproduced on the print according to the image data agrees with the objective density. In such a case, blurring of the text image tends to form when calibration is carried out so that the scene image is naturally reproduced, particularly when the color and detail reproduction in the portion of midscale to high density is naturally reproduced, and the reproduction of the scene image tends to be unnaturally when the calibration is carried out so that blurring of the text image does not form. Accordingly, it is necessary to repeat the calibration by trial and error while varying the exposure condition to obtain suitable reproduction of both the scene image and the text image. It is essential to overcome this problem.
JP O.P.I. No. 9-171237 discloses a method for inhibiting blurring of the text image by regulating the maximum gamma and the fill-in D.sub.max by digital exposure to improve the sharpness of the image in a high density region. However, there is considerable deterioration of the image quality of character when a density exceeding the fill in D.sub.max is reproduced, and there is no description in this publication regarding the natural reproduction of the scene image. JP O.P.I. No. 10-20461 discloses a method for improving the quality of a text image by regulation of the dynamic range and the N value (degree of blurring). However, in such technology, the color balance in the edge portions of the text image tends to be lost in a high density region exceeding 2.0. It is demanded to improve such a problem.
Many kinds of digital image exposing apparatus are available in the market, and many kinds of apparatus are newly being developed accompanied with progress in light sources and controlling means. An apparatus using a generated light source having a sharp wavelength distribution, such as a laser or LED, is become the mainstream of digital image exposing apparatus. However, the kind of lasers or LEDs is not unified. Accordingly, the wavelength of the exposure light is often different for each apparatus. It has been found that a beautiful print without any blurring of the image in one exposing apparatus and blurring is tends to form in a high density region or unnatural reproduction of the scene tends to occur in another apparatus, which uses light of a different wavelength. Such a problem can be solved by optimizing the light-sensitive material for each of the apparatus. However, such is not practical to respond to the problem, since many kinds of digital exposing apparatus are available on the market, and it is expected that there will be a further increase in this kind of apparatus in the future. Under such conditions, an image forming method is demanded, whereby a beautiful print can be obtained using any exposure apparatus.